The disclosures herein relate generally to electrical voltage adapters and more particularly, AC to DC voltage adapters for electronic devices such as computer systems.
Many of today's airline, automobile and train passengers carry portable electronic devices such as notebook computers on-board for in-transit use. However, as computers consume large amounts of power, the batteries that operate the device do not last for more than typically 2-6 hours. On long trips or when the battery is weak, a computer can drain the battery quite rapidly. For the traveler attempting to minimize the weight of their computer luggage, heavy spare batteries are undesirable and still only provide a nominal amount of additional computer operating time.
Because the use of computers aboard airplanes is so common, some airlines have begun offering in-seat power systems for powering devices such as notebook computers. These power systems use an in-seat connector that is typically either a modified version of the standard auto cigarette lighter socket or a manufacturer specific plug configuration. In either case, some type of adapter is generally needed to connect with the computer to the in-seat connector.
The PRIMEX Aerospace Company (PAC) manufactures the EMPOWER in-seat power supply system. This system furnishes safe, DC power directly at the seat to permit uninterrupted laptop computer operation and battery charging throughout the flight. This eliminates concerns of batteries running out during in-flight usage. Furthermore, DC voltage is desirable as this is the type of voltage that notebook computers are designed to use as an input voltage.
The EMPOWER in-seat power system supplies approximately 15 VDC (volts DC). The typical automobile cigarette socket provides approximately 12 VDC. Because the level of power provided by different DC power sources varies from one power source to another, an adapter for providing the correct voltage for a specific computer is sometimes needed. For example, the EMPOWER in-seat power system requires the use of a special adaptor cord such as the POWEREXTENDER offered by Xtend Micro Products for enabling connection and voltage regulation to a device.
The POWEREXTENDER plugs into the in-seat power socket to provide an auxiliary source of power for operating the computer or for recharging the computer battery. The POWEREXTENDER takes the 15 volts from the airplane and converts it into the specific voltage required by the computer. Depending on the manufacturer and the model of the computer, a specific operating voltage may be required. Laptop computers manufactured by DELL Computer Corporation are designed to operate on any voltage within a range of from about 8 volts to about 19 volts. As a result, it is not necessary for the 15 volts provided by the EMPOWER in-seat power supply system to be converted to a different voltage.
Other solutions for converting and supplying DC power to electronic devices also exist. In the case of converting a supplied DC voltage to a voltage suitable for a computer, an adapter is available that converts a supplied DC voltage to 120 volts AC such that a standard AC adapter can then convert the AC voltage back to the DC voltage required by the computer. In the case of the EMPOWER in-seat power system, an adapter for allowing a device with a standard automobile cigarette lighter plug to be connected to the EMPOWER plug is available.
AC adapters are well known in the art. U.S. Pat. Nos. 5,698,964 and 5,864,457 disclose AC adapters for use with DC voltage operable devices such as notebook computers. The adapters disclosed in these references include a voltage converting portion for converting an AC voltage to a DC voltage and a voltage regulating portion for maintaining the DC voltage within a desired range. The inventive aspects of the illustrative embodiments presented herein may be applied to AC adapters known in the art such as those disclosed in these two references.
None of the current solutions teach a simple, compact and cost-effective apparatus for providing AC to DC converting as well as permitting interconnect capability to a remote DC voltage power supply such as an in-seat power supply system used on airplanes. Accordingly, a need has arisen for an apparatus that is configured to overcome the shortcomings of current techniques and constructions. In particular, a need has arisen for an apparatus for electronic devices such as notebook computer systems that can provide AC to DC power conversions as well as enable direct connection to a DC power source such as the EMPOWER in-seat power supply system.